import java.util.LinkedList;
import java.util.Queue;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 17655
 * Date: 2025-02-25
 * Time: 12:09
 */
public class test2 {
    /**
     * LeetCode 岛屿的最大面积
     */

    int[] dx = {0,0,1,-1};
    int[] dy = {1,-1,0,0};
    int m,n;
    boolean[][] vis = new boolean[51][51];


    public int maxAreaOfIsland(int[][] grid) {
        m = grid.length;n=grid[0].length;
        int ret = 0;
        for(int i=0;i<m;i++){
            for(int j=0;j<n;j++){
                if(grid[i][j]==1 && !vis[i][j]){
                    ret = Math.max(ret,bfs(grid,i,j));
                }
            }
        }
        return ret;
    }

    public int bfs(int[][]grid,int i ,int j){
        int count = 0;
        Queue<int[]> q = new LinkedList<>();
        q.add(new int[]{i,j});
        vis[i][j] = true;
        count++;
        while(!q.isEmpty()){
            int[] t =q.poll();
            int a = t[0],b=t[1];
            for(int k=0;k<4;k++){
                int x = a+dx[k];
                int y = b+dy[k];
                if(x>=0 && x<m && y>=0 && y<n && grid[x][y]==1 && !vis[x][y]){
                    q.add(new int[]{x,y});
                    vis[x][y] = true;
                    count++;
                }
            }
        }
        return count;
    }
}
